Muv has a real nice video on it - I posted it somewhere on the 15 clone info... you might have to read or scan a lot to find it. Link:
http://www.quiltingboard.com/picture...p-t164361.html anyway these thread the same. I thread mine over the top into the notch, through the tension, through the spring over the bar and then through the take up lever and back down. You may need to be sure to have regular thread and a felt pad on the spool spindle. If you use the kind of thread that comes off over the top or a very tall spool, you may need something to keep things moving the right way. I think Joe has posts about that on here somewhere.